This invention relates generally to vehicular processor-based systems.
A number of processor-based systems may be used in vehicles such as automobiles or trucks. Conventionally, an engine controller is utilized to control the operation of the engine. A body controller may be utilized to control all other operations of the vehicle such as remote opening of doors, controlling radios and the like. In addition, vehicles may include processor-based systems for providing conventional personal computer functions. For example, in car personal computers may provide routing and mapping information as well as entertainment through a compact disc or digital video disc player. Thus, a variety of conventional computer functions including mapping functions, music, movies and game functions may be provided through the in car personal computer.
In most personal computers, it is desirable to have at least one lower power consumption state. Particularly, in battery powered systems, it is desirable to reduce power consumption during periods of inactivity. Thus, some processor-based systems used in vehicles may have lower power consumption states such as suspend-to-RAM (STR) or suspend-to-non-volatile memory (STN). The STR mode may be a reduced power consumption mode that still continues to use some power. However, the system can generally be reactivated more quickly from the suspend-to-RAM state than from the suspend-to-non-volatile memory state.
A problem arises in connection with vehicular processor-based system when the engine is cranked. Conventionally, when the engine is cranked, the available power is greatly reduced for a period of time. A processor-based system, that is not in its reduced power consumption state, may be adversely affected by the reduced power condition. Generally, if nothing else is done, the processor-based system experiencing such a reduced power condition may shut itself down and automatically reboot.
In connection with processor-based systems such as those used for in car personal computers, this rebooting sequence delays the initiation of the personal computer. It would be disconcerting to the user if every time the user turns the engine on, the in car personal computer attempts to come on, fails and then reboots. As a result of this sequence of operation, a delay period may be created before the processor-based system may be accessed.
One available solution for this problem is to provide a potential source, such as a battery, in association with the vehicular processor-based system. However, this solution tends to be unreliable. For example, providing a battery in association with the processor-based system may require replacing the battery periodically. Thus, the user is burdened with special care instructions for the in car personal computer. In addition, requiring an additional battery or other potential source raises the cost of the overall computer system.
Thus, there is a continuing need for a better way to adapt vehicular processor-based systems to the period during cranking when the available power is reduced.